 | Halbach, P., Gursky, H.-J., Gursky, M.M., Schmidt-Effing, R., Maresch, W.V. (1992) Composition and formation of fossil manganese nodules in Jurassic to Cretaceous radiolarites from the Nicoya Ophiolite Complex (NW Costa Rica) Mineralium Deposita, 27 (2) doi:10.1007/bf00197101 | Journal (article/letter/editorial) | | Cretaceous radiolarites from the Nicoya Ophiolite Complex (NW Costa Rica) P. Halbach z, H.-J. Gursky 2,...radiolarian cherts within the Nicoya Ophiolite Complex (NW Costa Rica). Field studies, X-ray diffraction...mm to 9 cm dominate. They are characterized by braunite, hollandite, pyrolusite and quartz as well as...(todorokite?) was altered during thermometamorphic (braunite) and hydrothermal (hollandite, pyrolusite) events...study it is shown that under special conditions, braunite can be produced from modern nodule material. |  | | Journal (article/letter/editorial) | | EXHAL.47'II 'E MANGANESE OPHIOLITE COMPLEX, DEPOSITS OF THE NICO YA COSTA RICA Introduction productionof...most promising manganesedeposits of the Nicoya Peninsula, Costa Rica, were studied. Selec- group of workingsnear...(1962) Nicoya ophiolite complex. sites show old small-scaleworkings. The largest This complex, which...PUNTA 3 SANTA ROSA GORDA I6 PARAI SO o COST NICOYA o I7 I8 I10 III PACIFIC OCEAN 112 AN JU...the main manganiferous areas in the Nicoya Pen{nsula, Costa Rica' occurrencesof massive sulfide bodies |  | | Journal (article/letter/editorial) | | Falotta and Parsettens (Oberhalbstein, Grison Canton, Switzerland) are enclosed in Upper Jurassic radiolarites...transformed gradually into a poorly crystallized braunite (with a large excess of SiO2). In contrast, the...of the nodules is composed of well-crystallized braunite with normal (10 wt%) contents of SiO2. Narrow...cryptomelane-hollandite isostructural series crosscut the braunite mineralization, and represent a secondary paragenesis...in these nodules - and the first observation of braunite microstructures in a metamorphic area. The occurrence |  | | Journal (article/letter/editorial) | | The Buckeye manganese mine in the Franciscan Complex of the California Coast Ranges is associated with...rhodochrosite, gageite, Mn-oxides (hausmannite, braunite), divalent Mn-silicates (caryopilite, taneyamalite...have fiat patterns (seawater × 7.104) whereas braunite-rich layers are more enriched (seawater × 2-105)...hausmannite were deposited from the most reduced fluids, braunite from intermediate mixtures, and Mn-silicates from...formula Analogues Rhodochrosite Hausmannite Braunite Gageite Caryopilite Taneyamalite Phase A Mg-rich |  | | Report (issue) | | anorthoslte-gabbro and magnetite ilmenlte in intrusive complex. PGE placers. Metal Concentrations NI, PGE, Cr...Gossan Geochemical Signature; Examples Stillwater Complex Cu, Ni, PGE, Co References Page (1977) Cumulus...anorthosite, minor troctolite > LAYERED STRATIFORM COMPLEX X X X X PGE zone Cumulus pyroxenite Chromite...Geochemical Signature; Examples Bushveld Stillwater Complex PGE, Cu, Ni References Vermaak & Hendriks (1976)...Layers may be cut by pipes and Fe, Ti, V Bushveld Complex References Williams (1969) and Molyneux (1969) |  | | Journal (article/letter/editorial) | | island-arc environment. The contrasting rhyolite–basalt complex of the Karamalytash Formation (Eifelian) belongs...Ulutau Formation (D2zv–D3fr1): tephroterrigenous complex; (8) Bugulygyr Horizon (D2ef): jasperite, jasper...Karamalytash Formation (D2ef): (a) basalt complex, (b) rhyolite–basalt complex; (10) Irendyk Formation (D1e–D2ef):...andesite–basaltic complex; (11) Baimak–Buribai Formation (D1e): (a) basalt complex with marianite, (b)...(b) basalt–andesite–dacite– rhyolite complex; (12) Upper Proterozoic (Riphean): metavolcanic and metasedimentary |  | | Journal (article/letter/editorial) | | (“oxidised”) ores were formed with the dominance of braunite. © 2012 Elsevier B.V. All rights reserved. 1...and exploration activities in the palaeovolcanic complex of the Urals fold belts. Therefore, further investigations...rhyolite-basaltic complex. The upper part of the volcanic section includes andesite-basaltic complex composing...composing the island-chain. The complex encloses up to 30% of dacites and rhyolites as well. Its thickness varies...a few tens of metres in the western part. An ophiolite association is developed to the west from the |  | | Book | | Deposits in Sedimentary Sequences of the Franciscan Complex, Diablo Range, California James R. Hein, Randolph...cooperation is valuable for the understanding of complex and widespread geologic phenomena. Because of the...during the world wars in the United States, Japan, Costa Rica, New Zealand, and elsewhere. Compared to fluvial...as a filtering agent is possible because of the complex and small size of pores in the diatom frustule...diagenesis (Kastner et al., 1977). When cherts in ophiolite sequences are incorporated into continental margins |  | Maslennikov, V.V., Ayupova, N.R., Herrington, R.J., Danyushevskiy, L.V., Large, R.R. (2012) Ferruginous and manganiferous haloes around massive sulphide deposits of the Urals. Ore Geology Reviews, 47. 5-41 doi:10.1016/j.oregeorev.2012.03.008 | Journal (article/letter/editorial) | | 1016/j.oregeorev.2012.03.008 The Urals is a famous province where jasper and Mn-jasper deposits are widespread...rocks can be testified by examples of limestone–ophiolite (Oman, Cyprus and Greece), and also limestone–dacite–rhyolite...typical umbers described in Troodos and Semail ophiolite, due to their higher degree of lithification, related...Mn-silicate, Mn-carbonate and Mn-oxides. Residual braunite predates the later Ca–Mn carbonates in the Mn-rich...overgrown (red) by apatite (between) and subhedral braunite (Fig. 17G, H). The similar pseudomorphic authigenic |  | Skowronek, Artur, Maciąg, Łukasz, Zawadzki, Dominik, Strzelecka, Agnieszka, Baláž, Peter, Mianowicz, Kamila, Abramowski, Tomasz, Konečný, Patrik, Krawcewicz, Artur (2021) Chemostratigraphic and Textural Indicators of Nucleation and Growth of Polymetallic Nodules from the Clarion-Clipperton Fracture Zone (IOM Claim Area) Minerals, 11 (8) 868 doi:10.3390/min11080868 | Journal (article/letter/editorial) | | Only single traces of pyrolusite, hollandite, or braunite are potentially found in the EPMA data, usually...oxyhydroxides. The formation of proto-thermal braunite may occur only at increased temperature and a...part of the CCFZ in the IOM claim area showed complex internal textures reflecting multistage nucleation...Cretaceous radiolarites from the Nicoya Ophiolite Complex (NW Costa Rica). Miner. Deposita 1992, 27, 153–160 |  | | Report (volume) | | to be a simple mineral may have turned into a complex group. A continuous update is necessary, and the...earth element epidote minerals developed into a complex group (see Gieré and Sorensen 2004), and the newly...used to be rather simple has turned into a quite complex mineral group. This chapter intends to serve as...composition of epidote, which results in a very complex irregular zoning pattern. Cr content varies from...through the peak stage of metamorphism, where complex zoning can be preserved (see also Grapes and Hoskins |  | Hodges, C.A., Cox, D.P., Singer, D.A., Case, J.E., Berger, B.R., Albers, J.P. (1984) U.S. Geological Survey-INGEOMINAS mineral resource assessment of Colombia. Open-File Report Vol. 1984 (84-345) US Geological Survey doi:10.3133/ofr84345 | Report (issue) | | planning future minerals exploration programs. The complex geologic history and varied lithologic environments...discovered and are currently being evaluated. The complex and varied geologic setting of the country is permissive...districts, particularly those having unusally complex mineralogy (such as the California-Vetas district)...(Sinu belt, South Caribbean deformed belt). (9) Complex ranges and small basins of the Guajira Peninsula...vein filling and associated stockwork deposits of complex silver sulfides, simple base-metal sulfides, and |  | | Report (volume) | | Diagram of a typical mafic-ultramafic stratiform complex 12 Cartoon cross-section of a typical komatiitic...chromite deposi a typical mafic-ultramafic stratiform complex 41 Chromite grades of pediform chromite deposits...Generalized geologic map of a zoned ultramafic complex 50 Tonnages of carbonatite deposits 52 Grades of...Generalized stratigraphic column through the Troodos ophiolite showing Cyprus massive sulfides and other deposit...unifying concept that explains or describes a complex phenomenon. In this context we shall apply only |  | | Journal (article/letter/editorial) | | Bornite Boulangerite Bournonite Braggite Brannerite Braunite Bravoite Brazilianite Breithauptite Breunnerite...mineralization may either be the product of a complex polyphase mineralizing process, reflecting a combination...intrusions of Archaean age such as the Bushveld Complex, South Africa. Stratiform Cr deposits account for...the Steelpoort region of the eastern Bushveld Complex. Stratiform deposits contain substantial reserves...1–420 47 Fig. 03.03. The Bushveld ultrabasic complex, South Africa (Fe, Cr, and PGE) and the Great Dyke | | | Journal (article/letter/editorial) | | Bornite Boulangerite Bournonite Braggite Brannerite Braunite Bravoite Brazilianite Breithauptite Breunnerite...mineralization may either be the product of a complex polyphase mineralizing process, reflecting a combination...intrusions of Archaean age such as the Bushveld Complex, South Africa. Stratiform Cr deposits account for...the Steelpoort region of the eastern Bushveld Complex. Stratiform deposits contain substantial reserves...1–420 47 Fig. 03.03. The Bushveld ultrabasic complex, South Africa (Fe, Cr, and PGE) and the Great Dyke |  | | Book | | affects its present characteristics as a minera1 province, because of the exposure of the various depth...colour index. This is, without doubt, the most complex lithologie association to be handled from the point...or in the mine workings at all. The Climax Mo complex is the best known example. Here three generations...150-200 km and are up to 15 km thick. The entire complex is composed of over 800 mappable plutons and small...1968; Fig. 28-7). Central Kazakhstan is extremely complex in geological terms. It remains an enigmatic accumulation |  | | Book | | affects its present characteristics as a mineral province, because of the exposure of the various depth...colour index. This is, without doubt, the most complex lithologic association to be handled from the point...or in the mine workings at all. The Climax Mo complex is the best known example. Here three generations...150-200 km and are up to 15 km thick. The entire complex is composed of over 800 mappable plutons and small...1968; Fig. 28-7). Central Kazakhstan is extremely complex in geological terms. It remains an enigmatic accumulation |
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